61. During which stage of meiosis do sister chromatids separate and move to opposite poles of the cell?
Answer: C
Sister chromatids separate and move to opposite poles of the cell during Anaphase II.
During Anaphase II, the sister chromatids are pulled apart by the spindle fibers and move toward opposite poles of the cell, ensuring that each daughter cell will receive an identical set of chromosomes.
A) Prophase II
Prophase II is the stage where the chromosomes condense and the nuclear envelope begins to break down, but the sister chromatids are still attached at their centromeres. Thus, they do not separate during this phase, making this option incorrect.
B) Prophase I
Prophase I is primarily focused on the pairing of homologous chromosomes and the exchange of genetic material through crossing over. The sister chromatids remain together during this stage, so this option does not address the separation that occurs in Anaphase II.
C) Anaphase II
Anaphase II is the correct stage in meiosis where sister chromatids are separated and pulled toward opposite poles of the cell. This separation is crucial for ensuring that each gamete receives the correct number of chromosomes, affirming that this is the correct answer.
D) Anaphase I
During Anaphase I, homologous chromosomes are separated, not the sister chromatids. The sister chromatids remain attached during this phase, making this option incorrect as it does not pertain to the separation of sister chromatids.
Conclusion
Anaphase II is definitively the correct answer as it is the stage in meiosis where sister chromatids are separated and move to opposite poles. Options A, B, and D fail to describe this critical event, focusing instead on stages where sister chromatids are not yet separated. Thus, Anaphase II is essential for the proper distribution of genetic material in gametes.